We know Oklahoma City is a contender — despite their little three-game blip as they re-adjust to Russell Westbrook in the lineup, they are still 21-7 when Kevin Durant and Russell Westbrook both play this season, they have a top-10 offense and defense when you look at points per possession. The same is true of the Spurs, and while they have had struggles against the NBA’s elite during the regular season last season’s run should remind you not to read too much into that. When the Spurs are healthy and focused they can compete with anyone.

But what about the next tier in the West? What about the Clippers? The Rockets? The Trail Blazers? Can any of those rise up and truly challenge OKC (the current bar for Best in the West).

Defining a contender can be a bit nebulous. It’s more like former Supreme Court Justice Potter Stewart effort to define test for obscenity — we know it when we see it. I don’t see it with Portland, I think the Clippers and Rockets are on the cusp but may not be there yet.

Here are a few numbers to help us get an idea, using NBA.com stats (including some from the Sports VU cameras).

• Portland came back to earth some in February — they had a point differential of +4.4 per 100 possessions, which is good enough for ninth in the NBA but more in the Charlotte/Washington/Toronto range than contender status. Their defense remained 11th in the NBA and their offense, now without LaMarcus Aldridge, can’t bail them out. I’ve not been sold Portland is ready to knock on the door of the contenders all season, nothing right now is changing my mind.

• The question with the Clippers remains defense — in February they allowed 105.6 points per 100 possessions, ranked 22nd in the league. Because of a stellar offense (114 per 100) they remain fourth in point differential through those 11 games, but that doesn’t mask the question of if they can get enough stops to win in the postseason.

• Opposing teams get a league-high 10.4 shots a game at the rim when DeAndre Jordan is on the court — he defends it well and they only hit 51.5 percent of them, but they get there.

• Glen Davis may actually help the Clippers defense — it’s not that he’s a great defender, he’s just better than Ryan Hollins and that is who loses minutes with Davis in the fold. Same with Danny Granger, who is no great wing defender but will be taking minutes from Jared Dudley.

• Houston on the other hand has the sixth best defense in the NBA since Feb. 1. They give up a lot of points per game because they play at the fourth fastest pace in the league but they defend their possessions well and are a very good transition defensive team.

• In February, teams finished a very high 63.2 percent at the rim against the Rockets — but they never get there. The Rockets gave up just 250 attempts at the rim in the month, only Charlotte did better (247, but they played one less game than Houston). (And yes, using raw numbers for a moth is a rough gauge, go the last 15 Rockets games and they are 20th in shots allowed at the rim and teams shoot 62.3 percent.)

• The Rockets are maybe the best first half team in the NBA — they are disciplined in forcing their style and sucking other teams into a pace the opponent is not comfortable with. It leads to big quarters, like the 42 they dropped on Sacramento this week. However in the playoffs that element of surprise goes away. Will the Rockets in the halfcourt suddenly be too much James Harden in isolation, and too much Dwight Howard in the post? Both of those can disrupt the Rockets’ offensive flow.

• The question with the Rockets in February was the toughness of the schedule — we will learn more soon. They lost to the Clippers on Wednesday but that was the second night of a back-to-back and their tired legs showed as their transition defense was not what it normally is. That said, their next eight games port the Rockets include the Heat twice, the Pacers, the Thunder, Trail Blazers and Bulls. That’s a legit test.

• My sense is the Rockets are closer — they are now getting quality minutes out of Omer Asik off the bench, he gives them depth of defense that the Clippers just do not have. That the Trail Blazers do not have. Houston also is starting to find its identity. They may need to learn a hard lesson in the playoffs this season, they may need to tweak the roster some, but they have grown toward being a contender this season in a way I haven’t fully seen with the Clippers yet.